Distribution of Acinetobacter baumannii in a neurointensive care unit

Area of Science:

• Medical Microbiology
• Infectious Diseases
• Critical Care Medicine

Background:

• Acinetobacter baumannii is an opportunistic pathogen frequently associated with hospital-acquired infections.
• Neurointensive care unit (NICU) patients are particularly vulnerable to multidrug-resistant organisms.
• Understanding colonization patterns is crucial for infection control in high-risk settings.

Purpose of the Study:

• To investigate the prevalence and characteristics of Acinetobacter baumannii colonization in NICU patients.
• To compare patient-derived strains with environmental isolates.
• To identify potential sources and transmission dynamics of A. baumannii in the NICU.

Main Methods:

• Prospective case-matched study over 1 month.
• Isolation and identification of Acinetobacter species using phenotypic properties and amplified ribosomal DNA restriction analysis (ARDRA).
• Epidemiological typing via Biolog system (carbon source oxidation), antibiograms, and restriction endonuclease analysis (REA).

Main Results:

• Acinetobacter baumannii was prevalent, simultaneously colonizing the respiratory tract and skin of NICU patients (stay >3 days).
• No A. baumannii was isolated from healthy controls.
• A single predominant A. baumannii strain colonized both skin and respiratory tracts in patients.
• Environmental strains were metabolically more active, more resistant, and had distinct REA profiles compared to patient strains.

Conclusions:

• A. baumannii frequently colonizes NICU patients, affecting both respiratory and skin sites with the same strain.
• Patient colonization appears to be patient-specific, with differing onset times.
• Environmental A. baumannii strains are distinct from those colonizing patients, suggesting different ecological niches or origins.